Abstract:
A ruthenium catalyzed method to synthesize cyclic sulfate compounds from the corresponding cyclic sulfites, and the cyclic sulfate reaction products obtained by this method. These cyclic sulfates further react with selected nucleophiles to give various substituted products. The method is an efficient means for the synthesis of chiral building blocks from tartaric acid enantiomers in high yields using an overall two-stage, one-pot reaction procedure. The chiral compounds can be transformed by nucleophilic reactions into chiral building blocks useful for the synthesis of natural biologically active products, such as antibiotics and pheromones.
Abstract:
An osmium-catalyzed method of addition to an olefin. In the method of asymmetric dihydroxylation of the present invention, an olefin, a chiral ligand, an organic solvent, water, an amine oxide an osmium-containing compound and, optionally a tetraalkyl ammonium compound are combined. In the method of asymmetric oxyamination of the present invention, an olefin, a chiral ligand, an organic solvent, water, an amine derivative, an osmium-containing compound and, optionally, a tetraalkyl ammonium compound are combined. In the method of asymmetric diamination of the present invention, an olefin, a chiral ligand, an organic solvent, a metallo-chloramine derivative or an amine derivative and an osmium-containing compound are combined. In one embodiment, an olefin, a chiral ligand which is a dihydroquinidine derivative or a dihydroquinine derivative, acetone, water, N-methyl morpholine N-oxide and osmium tetroxide are combined to effect asymmetric dihydroxylation of the olefin.
Abstract:
A convenient process for the regioselective synthesis of 1,5-disubstituted 1,2,3-triazoles and 1,4,5-trisubstituted 1,2,3-triazoles from organic azides and alkynes employs catalytic ruthenium.
Abstract:
A copper catalyzed click chemistry ligation process is employed to bind azides and terminal acetylenes to provide 1,4-disubstituted 1,2,3-triazole triazoles. The process comprises contacting an organic azide and a terminal alkyne with a source of reactive Cu(I) ion for a time sufficient to form by cycloaddition a 1,4-disubstituted 1,2,3-triazole. The source of reactive Cu(I) ion can be, for example, a Cu(I) salt or copper metal. The process is preferably carried out in a solvent, such as an aqueous alcohol. Optionally, the process can be performed in a solvent that comprises a ligand for Cu(I) and an amine.
Abstract:
A library of functionalized dendritic macromolecules was prepared in extremely high yields using no protecting group strategies and with only minimal purification steps through the use of copper(I)-catalyzed 1,3-dipolar cycloaddition of azides and terminal acetylenes.
Abstract:
Tert-alkyl sulfonamides chloramine salts are used as nitrogen sources in the catalytic aminohydroxylation and/or aziridination of olefins. The tert-alkyl sulfonamides chloramine salts are close to Chloramine T with respect to their reactivity as nitrogen sources with olefins. However, unlike the tosyl sulfonyl amine group of Chloramine T, the resulting t-alkyl sulfonylamino functionalities can be easily converted to an unprotected amine under mild acidic conditions making the method a simple and cost efficient approach for producing unsubstituted hydroxy amine and/or aziridine products.
Abstract:
A method for the direct aziridination of olefins as well as a wide range of allylic alcohols employs phenyltrimethylammonium tribromide (PTAB) as a general and effective catalyst and N-sodio-N-chloro sulfonamides, chloramine salts, as the nitrogen source.
Abstract:
Osmium-catalyzed methods of addition to an olefin are discussed. In the method of asymmetric dihydroxylation of the present invention, an olefin, a chiral ligand, an organic solvent, water, an oxidant, an osmium-containing compound and an organic soluble anion are combined. The presence of the organic soluble anion allows the asymmetric dihydroxylation reaction to occur rapidly and the amount of olefin that is diydroxylated is high with concomitantly less chiral ligand and osmium-containing catalyst than previously achieved.
Abstract:
Osmium-catalyzed methods of addition to an olefin are discussed. In the method of asymmetric dihydroxylation of the present invention, an olefin, a chiral ligand, an organic solvent, water, an oxidant and an osmium-containing compound are combined. In the method of asymmetric oxyamination of the present invention, an olefin, a chiral ligand, an organic solvent, water, a metallo-chloramine derivative, an osmium-containing compound and, optionally, a tetraalkyl ammonium compound are combined. In the method of asymmetric diamination of the present invention, an olefin, a chiral ligand, an organic solvent, a metallo-chloramine derivative, an amine and an osmium-containing compound are combined. In one embodiment, an olefin, a chiral ligand which is a polymeric dihydroquinidine derivative or a dihydroquinine derivative, acetone, water, a base, an oxidant and osmium tetroxide are combined to effect asymmetric dihydroxylation of the olefin.
Abstract:
A ruthenium catalyzed method to synthesize cyclic sulfate compounds from the corresponding cyclic sulfites, and the cyclic sulfate reaction products obtained by this method. These cyclic sulfates further react with selected nucleophiles to give various substituted products. The method is an efficient means for the synthesis of chiral building blocks from tartaric acid enantiomers in high yields using an overall two-stage, one-pot reaction procedure. The chiral compounds can be transformed by nucleophilic reactions into chiral building blocks useful for the synthesis of natural biologically active products, such as antibiotics and pheromones.